Geomechanical challenges in petroleum reservoir exploitation

Abstract

Petroleum geomechanics deals mainly with coupled problems requiring simultaneous consideration of changes in temperature, pressure, stress, and chemical potential (THMC). Major current challenges in this domain include: accurate delineation of in situ physical properties and conditions (T, [σ ], p), especially for naturally fractured reservoirs; wellbore wall stability predictions in swelling and fractured shale strata; modeling and monitoring of multiple-stage hydraulic fracturing used for development of resources in low-permeability rocks; controlling or exploiting sand ingress into producing wellbores; predicting subsidence accurately enough so that rational design decisions can be made; mitigating or reducing the incidence of casing shear arising from subsidence or thermal reservoir stimulation; understanding and analyzing thermal production processes in viscous oil reservoirs; monitoring of deformations in and around reservoirs being subjected to complex processes; and, a newer development, using the deep sedimentary basin environment for the permanent and secure disposal of fluid and granular wastes. Given the importance of fossil fuel energy in our industrial societies ( >80% of all primary energy provision), the rewards for better engineering are significant.

Magmas near the critical degassing pressure drive volcanic unrest towards a critical state

“…Steam injection, which is a technique used in the oil industry for extracting heavy oil53, demonstrates that heating can affect ground deformation to a much larger extent than that expected from pure thermal expansion. Steam injection and the associated latent heat release deform the media also via thermally induced shear dilation54 and enhancing fluid-flow permeability. We conclude, therefore, that the CDP concept may contribute to explain acceleration in signals observed during volcanoes unrests.…”

Experimental study of mechanical properties of gypsum soaked in brine

“…Since the Malpasset Dam disaster in 1959 and the Vajont rock slide catastrophe in 1963, water impact on rock mechanical properties has attracted rock mechanics and rock engineering interest. In recent years, chemical issues coupled with temperature effects [1] have been added to the rock mechanics interest focus, especially on underground projects involving injection and production of fluids or heat, placement of nuclear or other solid waste, and various geomechanics issues in other technologies such as fossil fuel production [2]. New experiments ranging in scale from the laboratory to the full field scale have become more common [3], and various useful coupled process results obtained, often involving mechanical water-rock interaction.…”

A Micromechanical Model to Estimate Borehole Collapse Pressure

“…Damage theory uses "loss of functionality" idea rather than "loss of strength" to describe material failure process [2]. It means, however a material loses its strength after yield point, it is may be usable as a structure.…”